1. Technical Field
This application relates to a surgical device for removing tissue and more particularly relates to a surgical tissue biopsy device insertable through a small incision in the body.
2. Background of Related Art
Over 150,000 women in the United States alone are diagnosed each year with breast cancer. A biopsy of breast tissue is indicated when a breast abnormality is found, allowing removal of the tissue and testing to determine whether the abnormality is malignant and further surgery is necessary. Early diagnosis and removal of cancerous tissue is critical for successful treatment as early detection greatly increases the chances of survival.
Numerous devices are currently available for performing breast biopsies. These devices function to dissect a portion of the breast tissue and remove it from the body for pathology to determine whether the tissue is malignant.
The most invasive procedure is referred to as open excisional biopsy. In this procedure, large tissue samples are surgically removed, requiring long recovery times, risking disfigurement of the breast, increased scarring and increased morbidity.
In an attempt to overcome the disadvantages of open surgery, more minimally invasive instruments have been developed. One minimally invasive approach utilizes a percutaneous instrument referred to as a fine needle biopsy instrument. In this instrument, a needle and syringe are inserted directly through the breast into the target tissue, e.g. the lump, to remove a cell sample for pathology. One disadvantage of this technique is that numerous cell samples are required to be taken from the tissue to obtain a sufficient mass for testing, thereby requiring numerous needle sticks and increasing the time required for the procedure. Another disadvantage is that careful locational tracking of the tissue cells removed is required for accurate analysis. Also, with these devices there is a greater potential for false negatives due to the small sized specimens being removed without removal of sufficient surrounding areas of healthy tissue for comparison.
Another type of minimally invasive device is referred to as core needle biopsy. This device has a spring actuated cutter and obtains a larger specimen than the fine needle biopsy instruments. The specimen is suctioned into a side window in the needle and then back through the proximal end of the needle. Although larger than fine needle biopsy instruments, these needles are still relatively small, e.g. 2 mm in diameter. Since typically removal of between five and twenty tissue cores of 2 mm in diameter and 20 mm in length is required for accurate pathology, five to twenty needle sticks into the patient of this 2 mm diameter needle is required. These devices also have the disadvantage that the spring force cutting action may displace malignant cells into the adjacent normal tissue. Also, the amount of false negatives can be high because of inadequate removal of surrounding healthy tissue. Like fine needle biopsy, success and accuracy of the procedure is skill dependent because the device must be maneuvered to various positions and these different positions accurately tracked.
Another disadvantage common to both fine needle and core needle biopsy devices is that the entire lesion cannot be removed. Therefore, if the tests show the lesion is malignant, another surgery must be scheduled and performed to remove the entire lesion and surrounding tissue. Besides the additional cost and surgeon time, this can have an adverse psychological affect on the patient who must await the second surgical procedure.
Some percutaneous devices, such as the Mammotome marketed by Ethicon, Inc., attempted to overcome some of these disadvantages of percutaneous devices by enabling multiple specimens to be removed with a single needle stick. The specimens are removed from the proximal end of the needle by a vacuum. Although overcoming some disadvantages such as reducing the number of needle sticks, the Mammotome still fails to overcome many of the other drawbacks since careful tracking is required, success is skill dependent, and a second surgery is necessary if the lesion is malignant, with the attendant expenses and trauma.
In an attempt to avoid a second procedure, the ABBI instrument marketed by United States Surgical Corporation provided a larger needle so that the entire specimen and tissue margins could be removed. The extra tissue excised is achieved by a larger diameter cannula. The cannula removes breast tissue from the skin surface entry point to the interior region of the breast where the lesion is located. The advantage of this instrument is that if pathology indicates the tumor is malignant, then an additional surgical procedure is not necessary since the tumor and margins were removed by the large cannula. However, a major disadvantage of this instrument is that if pathology indicates the lesion is benign, then a large tissue mass would have been unnecessarily removed, resulting in more pain, a larger scar, and possible disfigurement of the breast. Thus, ironically, the instrument is more beneficial if the tumor is malignant, and disadvantageous if the tumor is benign. In either case, the instrument has the further disadvantages of causing additional bleeding because of the large incision and requiring closure of a larger incision, thereby increasing scarring, lengthening patient recovery time, and adding to the cost, time and complexity of the procedure.
It would therefore be advantageous to provide a surgical breast biopsy device which can access the targeted lesion through a small incision but be able to remove the entire lesion and margin, thereby avoiding the necessity for a second surgery. Such device would advantageously reduce the risk of cancer seeding, provide more consistent testing, reduce surgery time, reduce bleeding, and minimize disfigurement of the patient's breast.